Machine for grinding edges of glass articles

ABSTRACT

A machine for grinding the edges of glass articles such as slides for carrying specimens to be observed under a microscope. These glass articles are held in a suitable frame with the edges which are to be ground in engagement with a rotary grinding wheel. During the grinding operations a transmission is operatively connected with the frame to move the latter radially with respect to the axis of the grinding wheel so that in addition to the rotary movement of the grinding wheel there is the radial movement of the frame with the glass articles held thereby.

in United States atent [15] 3,641,712

Menzel Feb. 15 1972 [54] MACHINE FOR GRINDING EDGES OF FOREIGN PATENTS OR APPLICATIONS GLASS ARTICLES 86,234 8/1920 Switzerland 751/122 [72] Inventor: Gerhard Menzel, Braunschweig, Germany 15,877 12/ 1885 Great Britain ..5 1/ I 22 [73] Assignee: Propper Manufacturing Company, Inc. Primary Examiner Hamld D Whitehead Filedi 1969 Attorney-Blum, Moscovitz, Friedman & Kaplan [21] Appl. No.: 880,588 [57] ABSTRACT [52] U.S.Cl ..51/122 A machine f r grin ing th edg of glass anicles such as [51] Int. Cl ..B24b 9/08 slides for y g specimens to be Observed under a [58] Field of Search ..51/ 122, 125 microscope. These glass articles are held in a suitable frame with the edges which are to be ground in engagement with a References Cited rotary grinding wheel. During the grinding operations a transmission is operatively connected with the frame to move the UNITED STATES PATENTS latter radially with respect to the axis of the grinding wheel so 794,375 7/ 1905 Nazel ..5 1/ 121 X that in addition to the rotary movement of the grinding wheel 2,797,53 7/195 122 there is the radial movement of the frame with the glass arti- 1,077,306 11/1913 Root.... .....51/122 l h ld th b 2,361,514 10/1944 Tillyer. .....51/l22 1,985,817 12/1934 Celinski ..51/125 5 Claims, 2 Drawing Figures 6 l" c q K m4 NSM/SS/ON ":1 GE A E L P l I L A r i \Q. A I 1 IVLA r 7 I i i t 1 i i' I I 1 I :-T H F a 1 1 1' 3a V 1 l j y i MACHINE FOR GRINDING EDGES OF GLASS ARTICLES BACKGROUND OF THE INVENTION The present invention relates to machines for grinding glass articles.

In particular, the present invention relates to machines for grinding the edges of articles such as glass plates, in particular slides for carrying specimens of the type which are to be observed through a microscope.

Although many attempts have been made to carry out operations of this type in an economical and technically perfect manner, these objectives have not yet been achieved.

Usually a group of such articles are treated as a unit while held in a suitable holder with the edges of the articles engaged by the grinding surface of a rotary grinding disc or wheel. While suitable results are achieved in this way, experience has nevertheless shown that with these conventional operations there are unavoidable formations of roughness and slight grooves in the ground surface inasmuch as the individual grains of the grinding material which cannot all be situated precisely in one ideal grinding plane, unavoidably cross at the grinding location to result in these small grooves which provide the undesired roughness of the ground surface. For the same reasons the grinding dust which results from the grinding operations remains always at the same localized area on the grinding wheel, where this dust collects and reduces the grinding action of the grinding wheel inasmuch as this factor also results in the formation of tiny cracks in the surface which is ground.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a machine which will avoid the above drawbacks and which will enable edges of articles of the above type to be efficiently ground in an economical and technically perfect manner.

In particular, it is an object of the invention to provide a construction which will avoid the formation of any roughness in the ground surface.

Especially it is an object of the invention to provide a construction which will avoid the formation of tiny cracks, grooves or the like in the ground surface.

According to the invention the frame which holds the articles with their edges in engagement with the rotary grinding wheel is itself moved by a moving means described below, radially with respect to the axis of the grinding wheel so that the grinding operations do not take place at one localized area inasmuch as the articles are radially moved simultaneously with their engagement by the rotary grinding wheel. This movement takes place back and forth along radial paths.

Highly acceptable results, with an efficient mechanism which is simple and inexpensive to manufacture, have been achieved with the invention by using as a drive for the frames which hold the work a suitably shaped cam or eccentric mounted on the shaft which carries the grinding wheel with this cam or eccentric having its own self-contained drive. It has been found particularly desirable to provide for the eccentric or cam a plate having formed at its underside a camming groove in order to receive a cam follower, in the form of a roller, for example, carried by an arm which transmits movement from the cam follower to the holding frame which holds the articles such as the glass slides referred to above.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a schematic top plan view of one possible structure according to the invention, FIG. 1 showing only enough structure to afford a complete understanding of the invention; and

FIG. 2 is a partly sectional schematic front elevation of the structure illustrated in FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now to the drawings, there is schematically illustrated therein a housing 1 which not only houses the driving motor 2 but which also serves to support the entire assembly. The motor 2 is connected through any suitable conductors to a source of energy and includes unillustrated details such as a switch for turning the motor on and off. The motor drives a shaft 3 which extends upwardly beyond the housing I and which fixedly carries the grinding wheel 3a, the axis of which coincides with the axis of the shaft 3. The cam or eccentric referred to above takes the form in the illustrated example, of a circular disc or plate 4 eccentrically surrounding the shaft 3 and supported at the illustrated elevation thereon by an unillustrated collar which is situated beneath the plate 4 on the shaft 3 and fixed thereto by a suitable setscrew or the like.

This disc or plate 4 is formed in the illustrated example at its underside which is directed toward the grinding wheel 31:, with an annular camming groove 5 which also is eccentrically posi tioned with respect to the axis of the grinding wheel. This camming groove 5 receives a pair of diametrically opposed cam followers in the form of rollers 6 respectively supported for free rotary movement by a pair of substantially rigid arms which extend from the plate 4 along a common horizontal axis which is perpendicular to the vertical axis of the shaft 3.

These arms which carry the diametrically opposed followers 6 are themselves fixed to a pair of diametrically opposed holders 7 forming a pair of frame means each of which serves to hold the glass slides 8 in the attitude shown most clearly in FIG. 2. For example, the holders 7 are each in the form of rectangular frames having opposed inclined inner surfaces at their left and right walls, as viewed in FIG. 2 so that the slides 8 will be held in the position shown schematically in FIG. 2 with their lower edges in engagement with the upper grinding surface of the wheel 3a. Suitable guides which are not illustrated are provided to guide the holders or frame means 7 only for movement along the horizontal central axis along which the arms which carry the rollers 6 extend, these arms of course being fixed with the frames 7. For example, the pair of holders 7 may be situated between and in slidable engagement with a pair of stationary guide bars carried in any suitable way by the housing 1 and situated equidistantly from and on opposite sides of the horizontal central axis indicated in FIG. I. In this way the pair of frame means 7 can be reciprocated back and forth to the left and right, as viewed in FIG. 1, between the solid and dotted line positions illustrated. Thus, the edges of the slides 8 which are to be ground are maintained in engagement with the rotary grinding wheel 3a, and at the same time a drive means is provided for reciprocating the frame means 7 back and forth during rotary movement of the grinding wheel 3a.

While it is indeed possible to provide a fixed connection between the plate 4 and the shaft 3 so that the plate 4 rotates and reciprocates the holders 7 in response to rotation of the shaft 3, such an arrangement, while advancing the present state of the art, nevertheless would result in a predetermined unchanging relationship between the manner in which the frame means 7 are reciprocated radially with respect to the axis of the shaft 3 during the rotation of the grinding wheel 3a, so that the glass slides 8 would be reciprocated in an unchanging manner with respect to the rotary grinding wheel 3a. It is therefore preferred to provide for the rotary cam or eccentric 4 an independent, self-contained drive such as the drive 70 which has no relationship to the manner in which the grinding wheel 3a is driven by the motor 2, so that in this way there is a purely haphazard relationship between the rate of reciprocation of the work radially with respect to the rotating grinding wheel. Particularly desirable results are achieved with such construction. The self-contained independent drive 7a may take the form of an annular motor surrounding the shaft 3, maintained stationary through any suitable unillustrated supporting elements, and operatively connected with the disc 4 so as to rotate the latter about the axis of the shaft 3. However, this independent drive 7a may simply take the form also of a gear fixed at one of its ends to the plate 4 which is freely rotatable with the gear about the axis of the shaft 3, and any desired transmission may coact with such a gear 7a for rotating the latter from any suitable source which may even be a variable drive so that the rate of reciprocation of the frames 7 can be varied in a haphazard manner during rotary movement of the grinding wheel 3a.

As a result of the above-described structure of the invention individual localized areas of the grinding wheel will always come into contact with different portions of the edges which are to be ground, so that the formation of tiny cracks or grooves in the ground surfaces which could not be avoided up to the present time, is indeed eliminated in a highly reliable manner with the structure of the invention. In addition, the rotary grinding wheel continuously operates with this construction in a manner which maintains the grinding areas substantially free of any falling grinding dust so that during the operations a far more efficient grinding is maintained.

It is particularly to be noted that the above-discussed advantages are achieved without any costly additions to the machine.

What is claimed is:

1. ln a machine for grinding the edges of glass articles such as slides for carrying specimens, frame means for holding the glass articles which are to have their edges ground, a grinding wheel engaging the articles held by said frame means for grinding the edges of the articles, said grinding wheel rotating about its axis during grinding of the articles, a shaft extending along the axis of the rotary grinding wheel, and moving means coacting with said frame means for moving the latter radially with respect to the axis of said grinding wheel during rotary movement of the latter, said moving means including a rotary drive member surrounding and rotatable with respect to said shaft, and a transmission extending from said rotary drive member to said frame means for reciprocating the latter radially with respect to the axis of the grinding wheel during rotation of said rotary drive member, said moving means including a drive operatively connected with said rotary drive member for rotating the latter independently of the rotation of said grinding wheel to provide for said frame means a reciprocation which has no relation with respect to the rotation of the grinding wheel.

2. The combination of claim I and wherein said moving means including a cam carried by said shaft for free rotation with respect thereto, said cam forming said rotary drive member and said drive being operatively connected to said cam for rotating the latter about said shaft independently of the rotation of the grinding wheel.

3. The combination of claim 2 and wherein said drive is a self-contained drive coacting with said cam for rotating the latter about the axis of said grinding wheel.

4. The combination of claim 2 and wherein said cam includes a plate formed with a cam groove, and a cam follower fixed to said frame means and received in said cam groove.

5. The combination of claim 4 and wherein said follower includes a roller received in said cam groove. 

1. In a machine for grinding the edges of glass articles such as slides for carrying specimens, frame means for holding the glass articles which are to have their edges ground, a grinding wheel engaging the articles held by said frame means for grinding the edges of the articles, said grinding wheel rotating about its axis during grinding of the articles, a shaft extending along the axis of the rotary grinding wheel, and moving means coacting with said frame means for moving the latter radially with respect to the axis of said grinding wheel during rotary movement of the latter, said moving means including a rotary drive member surrounding and rotatable with respect to said shaft, and a transmission extending from said rotary drive member to said frame means for reciprocating the latter radially with respect to the axis of the grinding wheel during rotation of said rotary drive member, said moving means including a drive operatively connected with said rotary drive member for rotating the latter independently of the rotation of said grinding wheel to provide for said frame means a reciprocation which has no relation with respect to the rotation of the grinding wheel.
 2. The combination of claim 1 and wherein said moving means including a cam carried by said shaft for free rotation with respect thereto, said cam forming said rotary drive member and said drive being operatively connected to said cam for rotating the latter about saiD shaft independently of the rotation of the grinding wheel.
 3. The combination of claim 2 and wherein said drive is a self-contained drive coacting with said cam for rotating the latter about the axis of said grinding wheel.
 4. The combination of claim 2 and wherein said cam includes a plate formed with a cam groove, and a cam follower fixed to said frame means and received in said cam groove.
 5. The combination of claim 4 and wherein said follower includes a roller received in said cam groove. 